Intel prepared new Lynnfield processors that should make Nehalem microarchitecture really mainstream and popular. Let’s find out if the new LGA1156 CPUs have any chance of ousting LGA775 and Socket AM3 solutions from the market and taking over the leadership.

Lynnfield CPU Lineup

Lynnfield processors are inferior to the existing Bloomfield CPUs not only in the number of channels of the integrated memory controller. Their clock frequencies are also different: cheaper Lynnfield processors will work at a slightly lower clock speeds. However, these differences don’t seem too significant that is why it is quite logical that Lynnfield processors will sell under the same trademark as Bloomfield, namely, Core i7.

However, the junior Lynnfield CPU model will nevertheless be assigned to a lower class family called Core i5, but unlike other desktop Nehalem CPUs it will have no Hyper-Threading technology support. So, it explains a lot in Intel’s logics in naming their processor models. Those quad-core processors that the OS sees as eight-core ones due to Hyper-Threading technology support will belong to Core i7 family. If the operating system sees the processor as a quad-core one, it will be called Core i5. Therefore, we can suppose that the Core i9 processor family will consists of upcoming six-core CPUs supporting Hyper-Threading technology, which are currently known as Gulftown. As for Core i3 processors, the logics will be different here: this family will include budget CPUs with limited functionality.

At first Lynnfield lineup will include three solutions with 2.66, 2.8 and 2.93 GHz clock speeds. It is very important that due to lower clock frequencies these processors will also boast lower 95 W thermal design power instead of 130 W as seen by the Bloomfield CPUs. As a result, these new processors can be considered a worthy replacement for Core 2 not only in performance but also in power consumption aspects.

The complete list of currently available Nehalem processors includes the following six models:

Since Lynnfield is very similar to Bloomfield on the microarchitectural level and actually differs only in its Uncore part, we shouldn’t be surprised to see identical primary specifications of the Core i7-900, Core i7-800 and Core i5-750.

The following features typical of the new Lynnfield processor structure make them related in many aspects to the existing Core i7-900 CPU models:

Elimination of the processor bus in its traditional form due to relocation of the PCI Express 2.0 controller directly into the CPU. This controller integrated into the processor provides support for 16 PCI Express 2.0 lanes, which can be used for one (in PCI Express x16 mode) or two (in PCI Express x8 mode) graphics cards.

Memory controller integrated into the CPU that supports dual-channel DDR3 SDRAM. Each memory channel can work with three unbuffered memory DIMMs.

Hyper-Threading technology support (only for top Lynnfield models from Core i7-800 family). It enables each Core i7-800 core to use two computational threads at the same time, which makes the operating system see each processor as an eight-core one.

8MB shared L3 cache.

Integrated PCU microcontroller that independently controls the voltage and frequency of each core and can automatically overclock individual cores in case the remaining ones are not fully utilized.

New SSE4.2 instructions support.

Core i7-800 and Core i5-700 are manufactured with 45 nm process and consist of 774 million transistors on a 296 mm2 die.

You can see that the new Core i7-900 processors and the new junior CPUs are related from the diagnostic CPU-Z utility reports. Namely, they read the following for Core i7-870 and Core i5-750 processors that we received in our lab:

Overall, everything looks exactly like by our good old friends – Core i7-900. The only thing that was a little confusing on the screenshots above is the QPI bus frequency. It is obviously a program glitch, because Lynnfield processors simply don’t have this bus. As for the CPU clock frequency, it is obtained as the multiplier multiplied by base clock generator frequency, which is traditionally at 133 MHz for all Nehalem processors.

Judging by the formal specifications, the new Socket LGA1156 is that significant difference between the new processors and Core i7-900. As you can see from the name, this socket features fewer pins than the LGA1366, which is actually not surprising at all, because the integrated memory controller has fewer memory pins and the QPI interface has been replaced with the common PCI Express.

Fewer contacts as well as smaller contact spots in the CPU allowed to make the processor and processor socket physically smaller, about the size of LGA775.

LGA775 (left), LGA1156 (center), LGA1366 (right)

However, if you look at the bottom side of the new solution, you will see that LGA1156 and LGA1366 processors are very different from one another. Although they are of similar size, Lynnfield has much more pins on the bottom:

LGA775 (left), LGA1156 (center), LGA1366 (right)

So, new Core i7-800 and Core i5-700 processors are incompatible with any old platforms and require their own LGA1156 mainboards. Moreover, new processors also need their own cooling systems. According to platform guidelines the cooler retention holes on LGA1156 mainboards should be spaced out at a smaller distance from one another than on LGA1366 mainboards, but at a farther distance than on LGA775 mainboards. Frankly speaking, since the typical heat dissipation of top LGA775 and LGA1156 platforms is the same, this differentiation of the cooling solutions is a little puzzling. However, the fact I undeniable: Core i7-800 and Core i7-700 require their own coolers.

At the same time we should say a few words about the boxed cooler that we received together with the Core i7-870 processor. Although this processor is the top solution in the Lynnfield family, the cooler for it is relatively small. Its aluminum heatsink with the copper heart is only 13 mm tall.

This is clear indication that Lynnfield processors are not as “hot tempered” as Bloomfield, for instance.